Assume a woman is rich enough. Is it permitted for her to keep 4 husbands "assuming she can do justice to all 4"? Would you like to be one of the husbands of the 4?
Do not apply literal translations of 1000 year old texts to today's world. Keeping 4 wives a 1000 years ago can be understood, but there is absolutely no reason today. Stop trying to push us back a 1000 years when science can help you in all fields.